This invention pertains to a bearing assembly including a unique retainer bearing which is locked to a housing in a manner to prevent axial and radial displacement of a worm gear shaft rotatably mounted in the bearing and to an assembly method and tool used in the method.
One example of the utility of the bearing assembly is in use in a window operator wherein rotation of a worm gear shaft having a worm gear engaging a worm wheel on an operator arm causes movement of a window. A structure of this general type is shown in U.S. Pat. No. 4,253,276, owned by the assignee of this application. In the prior structure, after the retainer bearing was threaded into position within the housing, it was held in place by use of an additional structural element, such as a pin, wedged between the threads of the bearing and the housing. This required handling of an additional structural element and the assembly steps associated therewith, with a resulting increase in the cost of the product.
One system for avoiding the use of the pin to lock the retainer bearing to the housing is shown in U.S. Pat. No. 4,445,794, wherein the retainer bearing is provided with a discontinuous external thread. Rotation of the retainer bearing, after being fully seated within the bore of a housing, causes stripping of the softer threads of the housing which locks the retainer bearing in the housing.
The present invention avoids the use of the pin to lock the retainer bearing in the housing and relies upon a special shaping of the exterior of the retainer bearing and location of a specially-shaped part of the retainer bearing at a particular location of the housing whereby a limited amount of material of the housing can be deformed, by staking, into interlocked relation with the specially-shaped part of the retainer bearing.